Multi-objective topology optimization of porous microstructure in die-bonding layer of a semiconductor

To enhance semiconductor efficiency, it is imperative to develop a die-bonding material possessing exceptional thermal conductivity and stress-shielding capabilities to safeguard semiconductor components from detrimental heat and destructive stress. In this study, we employed a multi-objective topology optimization approach to design a porous microstructure for the die-bonding layer of semiconductors, targeting high thermal conductivity and low shear modulus. The finite element analysis method for a representative volume element (RVE) facilitates computational evaluations of macroscopic mechanical and thermal properties arepsilong from a periodic microstructure. Our investigation commenced with the creation of an RVE generator for obtaining periodic microstructures featuring randomly distributed pores with controlled morphological features. A high-throughput evaluation of numerous generated microstructures explored the impact of volume fraction and pore connectivity on macroscopic shear modulus and thermal conductivity. Despite the high-throughput evaluation indicating that pore connectivity has minimal effect on properties, the multi-objective topology optimization, addressing the conflict between maximizing thermal conductivity and minimizing shear modulus, revealed that connected pores and dispersed distribution in the architected microstructure contribute to improved material performance. In this optimization process, we employed a weighted sum method to find optimal compromised microstructures. Anisotropic and orthotropic microstructures were designed, and the effects of volume constrains and weight factors on microscopic morphology were explored. Despite the high-throughput evaluation suggesting a limited impact of pore connectivity, the results from multi-objective topology optimization underscored the significance of connected pores and dispersed distribution in achieving superior material performance.